A person's limbs and joints are susceptible to pain and injury from impacts, abrasion, and sustained contact pressure. Various protective devices may be worn to relieve discomfort and reduce injury by absorbing impact energy and distributing applied loads over an extended contact area on a person's body. Protective devices may be worn to shield body parts from blunt force trauma, cuts, and abrasions. For example, a person may wear knee pads to reduce discomfort resulting from kneeling on a hard surface. Elbow pads may be worn to prevent joint injuries that may result from a fall or collision with a hard object. Shin guards and forearm guards may be used to protect limbs and may be combined with padded guards for joints in limbs or may be worn without guards or pads for joints. Foot guards or shoe covers may be worn to protect a foot from being injured by a dropped object.
Knee pads, elbow pads, and other protective devices may include one or more pairs of straps, ties, elastic bands, or other attachment means disposed to hold a pad made of a resilient, compressible material over a joint or limb. The straps or other attachment means may be placed in direct contact with a person's skin or may be worn over the person's clothing. A protective device may be shaped to conform to the curved surfaces of the joint or limb the device is intended to cover or may be flexible enough to conform to the limb when the straps are tightened. The device may be covered by a shell or cap made from a strong material such as a high-density polymer, an epoxy-fiber composite, metal, synthetic rubber, natural rubber, polysiloxane, fabric, or combinations of these materials. The shell or cap may be positioned to deflect or distribute energy from loads applied to a joint or limb and may be strong enough to withstand impacts and durable enough to withstand abrasion.
A problem common to many knee pads, elbow pads, shin guards, and forearm guards is the difficulty in keeping the device in a preferred position over a joint and/or limb while the person wearing the device moves about. Flexing a limb joint may cause the protective device to move away from the area the device is intended to protect due to the expansion and contraction of muscles, tendons, and other tissues. The device may slip away from its preferred position when an external force is applied to the device, for example when a person wearing knee pads moves about in a kneeled position. The protective device may slide or rotate away from the joint or protected part of a limb, leaving the protected area exposed to impact and contact pressure and possibly exposing the person wearing the pad to pain or injury.
Some devices attempt to maintain a stable position on a limb by gripping the limb with more than one pair of straps. A first pair of straps may wrap around a limb on one side of a joint to be covered by the device and a second pair may wrap around the limb on the opposite side of the joint, with the protective device extending across the joint between the pairs of straps. Some devices use more than one pair of straps on a same side of a joint to hold the device in a preferred position. Whether a pad or guard has one pair of straps or more than one pair, the repeated change in the outer shape of a limb from flexing and relaxing muscles may cause the straps to loosen or may cause the protective device to creep away from its preferred position over a joint while a person moves about. A person experiencing these problems may attempt to tighten the straps to hold the pad in a preferred position for protection and comfort. However, tightening the straps may impair the movements of muscles and tendons near a joint, reduce blood circulation, or cause bruising or chafing.
Some protective devices attempt to avoid positioning problems and discomfort caused by straps by inserting the device into a pocket in a garment or by clamping to a structure such as a strap, grommet, or ridge on a garment. Such protective devices may not be effective unless one also wears the associated modified garment. In some cases, parts of the modified garment interposed between the protective device and an external object may be damaged by abrasion, cutting, or impact. The protective device may be easily shifted away from a preferred position over a joint or limb by movements of the garment, possibly exposing the person wearing the garment to discomfort or injury. The cost of the modified garment may add to the cost of purchasing and using the protective device.